Star a and star b have measured stellar parallax of 1.0 arc second and 0.75 arc second, respectively. which star is closer? how do you know?

Star A is closer than Star B

Explanation:

As we know that in parallax method of distance measurement the angle subtended by the star when it covers a distance of one Parsec arc length, it is known as parallax angle

Here we can say

so we have

so here we have

angle subtended by Star A = 1 arc sec

angle subtended by star B = 0.75 arc sec

now we have

distance for star A is given as

distance of star B is given as

So star A is closer than star B